CN104993046A - MTJ unit and manufacturing method thereof - Google Patents
MTJ unit and manufacturing method thereof Download PDFInfo
- Publication number
- CN104993046A CN104993046A CN201510359389.3A CN201510359389A CN104993046A CN 104993046 A CN104993046 A CN 104993046A CN 201510359389 A CN201510359389 A CN 201510359389A CN 104993046 A CN104993046 A CN 104993046A
- Authority
- CN
- China
- Prior art keywords
- layer
- film
- magnetosphere
- cofeb
- thickness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Mram Or Spin Memory Techniques (AREA)
- Thin Magnetic Films (AREA)
- Hall/Mr Elements (AREA)
Abstract
The present invention discloses an MTJ (Magnetic Tunnel Junction) unit and a manufacturing method thereof. A layer of extremely thin metal layer is inserted in a magnetic layer thin film of an MTJ, so as to form a magnetic layer/metal layer/magnetic layer structure, the thickness of the inserted metal layer ranges from 0.5nm to 2nm, through artificial increase for the number of interfaces in the magnetic layer, perpendicular magnetic anisotropy of the interface is greatly enhanced, and the perpendicular magnetic anisotropy of the whole film structure can be improved objectively. According to the MTJ unit and the manufacturing method provided by the present invention, perpendicular magnetic anisotropy of the magnetic layer thin film is effectively improved through a diffusion effect of the metal layer with the specific type and thickness and an interface effect between the magnetic layer and the metal layer, at the same time, the thickness of the magnetic layer thin film with good perpendicular orientation is also increased, thereby providing a new breakthrough for manufacture of perpendicular magnetic anisotropy MTJ units and devices in industrial community.
Description
Technical field
The invention belongs to area of Spintronics, more specifically, relate to a kind of magnetic tunnel junction cell and preparation method.
Background technology
Along with novel computer, information and the develop rapidly of electronic information technologies such as communicating, high density, high speed, high write efficiency, the contour performance requirement of high reliability are proposed to the memory as its core component.Various semiconductor memory, as the memories such as static random access memory (SRAM:Static RandomAccess Memory), dynamic random access memory (DRAM:Static Random Access Memory) and flash memory (flash) have obtained further investigation because possessing respective advantage and applied widely.But along with reducing of device size, the development of above-mentioned memory encounters respective bottleneck, limit its development and application to a certain extent.In recent years, based on magnetic tunnel-junction (MTJ, Magnetic Tunnelling Junction) magnetic random memory owing to having the characteristics such as non-volatile, storage density is large, read or write speed is fast, excite the research interest of industrial circle and academia in world wide greatly.
Typical magnetic channel has three-decker: free layer (free layer), barrier layer (barrier layer) and reference layer (reference layer), as shown in Figure 1.By changing the direction of magnetization of memory cell free layer, high and low two resistance states just can be produced in the memory unit.The Different Effects TMR value of MTJ of the abarrier layer material of MTJ knot, because abarrier layer material understands the tunnelling behavior that directly affect electronics, determine the tunnel magneto of MTJ, the abarrier layer material of current main flow is MgO.And for the material mainly ferrimagnet (FM) of magnetic tunnel-junction free layer (free layer) and reference layer (reference layer).Free layer feature is easy magnetization, and namely the direction of magnetization can change, and adopts so general the soft magnetic material that coercive force is less.Reference layer requires that the direction of magnetization is fixed, and is usually made up of pinning layer and nailed layer.Nailed layer material is the same with free layer, adopts soft magnetic material.Pinning layer generally adopts the hard magnetic material that coercive force is larger, utilizes anti-ferromagnetic coupling interaction to fix the direction of magnetization of nailed layer.At present for the soft magnetic material mainly CoFeB of MTJ, it has the characteristic of low-coercivity, high spinning polarizability.Also have report, other Co base soft magnetic materials available or novel high spinning polarizability semi-metallic are as the soft magnetosphere material of MTJ.The hard magnetic material that can be used for MTJ at present has FePt, TbFeCo, Co (Fe)/Pt (Pd) multilayer film etc.
MTJ requires the performance requirement of low-power consumption, little operating current, high density, high speed.Although MTJ has good electrology characteristic at present, but can not rest to the optimization of circuit performance, and also there are relevant issues on business-like road:
(1) due under superelevation storage density situation, in face, sharply reducing of magnetism anisotropic film size can produce magnetization and crispatura or vortex domain structure, thus causes the information dropout that stores.And vertical magnetism anisotropic film material effectively can overcome magnetization crispaturas or vortex magnetic domain, be conducive to the stability that raising information stores, and theory calculate also foretells that the critical current density of the MTJ of perpendicular magnetic anisotropic will lower than magnetic anisotropy memory cell in face.In order to improve storage density and reduce its reset current, the perpendicular magnetic anisotropy improving MTJ is necessary.
(2) due to each layer thickness of MTJ film Rotating fields all very thin (less than 1nm, general thicknesses of layers is 1-10nm to most thin layer), therefore the difficulty of preparation technology is large.In addition, obtain perpendicular magnetic anisotropic, the thickness of CoFeB layer must very little (being less than 1.2nm), and this difficulty prepared by technique increases further.Therefore, in order to reduce technology difficulty, improve MTJ and prepare feasibility, it is necessary for increasing the magnetospheric thickness with perpendicular magnetic anisotropy.
Present stage people mainly optimize the performance of MTJ by changing the magnetospheric thickness of MTJ, annealing temperature and tectal kind, thickness etc.Cover layer common in document has Ta, Ti, NiFe etc., and tectal difference and thickness can have impact to the diffusion of the crystallization of CoFeB and B.And Ta is referred maximum cover layer, Ta is except having fabulous oxidation resistance, and Ta layer and Ta/CoFeB interface obtain perpendicular magnetic anisotropy (PMA) to Ta/CoFeB/MgO-based MTJs and also play a key effect.Therefore, the perpendicular magnetic anisotropy starting point of the present invention just of magnetic layer material is improved by increasing interface in magnetosphere film.
Summary of the invention
For the defect of prior art, the object of the present invention is to provide a kind of magnetic tunnel junction cell and preparation method thereof, be intended to solve existing magnetic tunnel-junction thermal stability low, the problem that storage density is low.
The invention provides a kind of magnetic tunnel junction cell, comprise substrate, be attached to the reference layer on described substrate, the free layer being attached to the barrier layer on reference layer and being attached on barrier layer; Described reference layer comprises the first magnetosphere, metal level and the second magnetosphere; Strengthen the interface perpendicular magnetic anisotropy in the first magnetosphere and the second magnetosphere by described metal level, improve the perpendicular magnetic anisotropic of whole reference layer.The present invention by inserting the very thin metal level of one deck in the magnetosphere film of magnetic tunnel-junction, the structure of formation magnetosphere (FM)/metal level (M)/magnetosphere (FM) strengthens the interface perpendicular magnetic anisotropy in magnetosphere, thus reaches the object improving whole film layer structure perpendicular magnetic anisotropic.Improve the thickness of overall rete simultaneously owing to inserting metal level, reduce technology difficulty.
Further, the first magnetospheric thickness is equal with the second magnetospheric thickness, and the thickness of metal level is 0.5nm ~ 2nm.
Further, the material of metal level is nonmagnetic material.
Further, the material of metal level is Ag, Ta, Ti, Al, Cu or Au etc.Owing to inserting the magnetic membrane material of one deck Ta metal level, the Ta insert layer in 0.5nm ~ 2nm thickness range due to its diffusion and with magnetospheric interface interaction, the magnetospheric vertical orientated of same thickness can be optimized.
Further, the material of metal level is Ag, and thickness is 1nm.Owing to inserting the magnetic membrane material of one deck Ag metal level, the Ag insert layer of 1nm due to its diffusion and with magnetospheric interface interaction, the CoFeB that can optimize same thickness is magnetospheric vertical orientated.
Further, magnetic tunnel junction cell also comprises the protective layer be attached on described free layer.
Further, the material of protective layer can be Ta, and thickness can be 5nm.
Present invention also offers a kind of method preparing above-mentioned magnetic tunnel junction cell, comprise the steps:
(1) on substrate, prepare the first magnetosphere by the method for magnetron sputtering, described first magnetosphere prepares metal level, and prepare the second magnetosphere on described metal level;
Wherein, described first magnetospheric thickness is equal with described second magnetospheric thickness, and the thickness of described metal level is 0.5nm ~ 2nm;
(2) on described second magnetosphere, barrier layer is prepared by the method for magnetron sputtering;
(3) on described barrier layer, free layer is prepared; Wherein the structure of free layer is identical with the structure of above-mentioned reference layer, and be all magnetosphere, free layer comprises the first magnetosphere, is attached to the metal level on the first magnetosphere, is attached to the second magnetosphere on metal level;
Wherein, described first magnetospheric thickness is equal with described second magnetospheric thickness, and the thickness of described metal level is 0.5nm ~ 2nm;
(4) on described free layer, prepare protective layer, thus obtain magnetic tunnel junction cell.
Wherein, the material of metal level can be Ag, Ta, Ti, Al, Cu or Au.
Preferred further, the material of metal level is Ag, and thickness is 1nm.
Wherein, in the method for magnetron sputtering described in step (1), sputtering power is direct current 20W; Adopt low sputtering power to reduce sputter rate, improve quality of forming film.In the method for magnetron sputtering described in step (2), sputtering power is radio frequency 100W.
Particularly, the method preparing above-mentioned magnetic tunnel junction cell comprises:
(1) on MgO substrate, reference layer is prepared, concrete grammar is the CoFeB film first being sputtered 1.2nm with CoFeB target by magnetron sputtering under the small-power of 20W, required metal targets (Ag or Ta etc.) is used to prepare the metal intercalation that thickness is t again, and then sputter the CoFeB film of 1.2nm, result in formation of the magnetic layer-structure of the improvement inserting the very thin metal intercalation of one deck in CoFeB magnetosphere;
(2) on the reference layer prepared, prepared the barrier layer of the MgO of 1nm by magnetron sputtering by MgO target;
(3) free layer of improvement preparation on the barrier layer prepared, method is consistent with the reference layer in step one;
(4) in order to protect prepared magnetic tunnel-junction not oxidized, we have added the Ta protective layer of one deck 5nm at top layer.
Wherein, the film sample of all Slag coating is all for substrate preparation with monocrystalline MgO (001).
Wherein, the Ar air pressure preparing environment of film sample is 0.5Pa.
Wherein, the sputtering power of the sputtering power of CoFeB to be the sputtering power of 20W, Ag be 20W, Ta is 40W.
The present invention by inserting the very thin metal level of one deck in magnetosphere film, add the interface number in magnetosphere, greatly enhance interface perpendicular magnetic anisotropic, objectively improve whole film layer structure perpendicular magnetic anisotropic, thus making magnetic tunnel-junction thermal stability high, storage density is high.
Accompanying drawing explanation
Fig. 1 is typical magnetic tunnel junction structure.
Fig. 2 (a) is traditional magnetic layer-structure schematic diagram, the magnetic layer-structure schematic diagram that Fig. 2 (b) improves for the present invention.
The structural representation of the magnetic tunnel junction cell that Fig. 3 embodiment of the present invention provides.
The reference CoFeB film of metal level is not inserted through 400 DEG C, the X-ray diffractogram after 1h annealing in process in Fig. 4 embodiment of the present invention.
Magnetic hysteresis loop in Fig. 5 embodiment of the present invention in the horizontal direction of the CoFeB film of individual layer and vertical direction.
The magnetic hysteresis loop in the horizontal direction of the CoFeB film of 1nm and 0.5nm Ag and vertical direction is inserted in Fig. 6 embodiment of the present invention; Wherein, (a) is insertion 1nm Ag, and (b) is for inserting 0.5nm Ag.
The MAE that in Fig. 7 embodiment of the present invention, individual layer CoFeB film and the VASP of film that inserts Ag metal level calculate and the contrast of experiment value.
Insert the magnetic hysteresis loop in the horizontal direction of the CoFeB film of 1nm and 0.5nm Ta and vertical direction in Fig. 8 embodiment of the present invention, wherein, (a), for inserting 1nm Ta, (b) is for inserting 0.5nm Ta.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
The present invention, by utilize and the method strengthening magnetosphere interface perpendicular magnetic anisotropic in magnetic tunnel-junction improves the perpendicular magnetic anisotropic of MTJ, provides a kind of magnetic tunnel junction cell and preparation method thereof, strengthens the interface perpendicular magnetic anisotropy in magnetosphere.
The present invention by inserting the very thin metal of one deck (Ag, Ta etc.) layer in magnetosphere film, as shown in Figure 2, form the structure of magnetosphere (FM)/metal level (M)/magnetosphere (FM), the thickness of this metal intercalation is 0.5nm ~ 2nm, strengthen the interface perpendicular magnetic anisotropy in magnetosphere, thus reach the object improving whole film layer structure perpendicular magnetic anisotropic.In mtj structure, because each magnetosphere is all very thin, (thickness is many within a few nanometer range, even less than 1nm, the thickness of hard magnetic pinning layer is generally also no more than 100nm), along with the reduction of magnetic layer thickness, in magnetosphere, the perpendicular magnetic anisotropic contribution of perpendicular magnetic anisotropic to whole film layer structure of magnetic crystal grain reduces, and the contribution of interface perpendicular magnetic anisotropic to the perpendicular magnetic anisotropic of whole film layer structure between magnetosphere and contiguous rete increases.Therefore, the present invention, by inserting the very thin metal level of one deck in magnetosphere film, artificially increases the interface number in magnetosphere, greatly enhances interface perpendicular magnetic anisotropic, objectively improve whole film layer structure perpendicular magnetic anisotropic.
The present invention is compared with existing magnetosphere single thin film, the present invention utilizes in Single Magnetic layer film, inserts the very thin metal level of one deck, the perpendicular magnetic anisotropy of magnetosphere film is effectively improve by the interface interaction between the diffusion of the metal level of particular types and thickness and FM/M, too increase the thickness of vertical orientated good magnetosphere film, for the preparation of industrial quarters perpendicular magnetic anisotropy MTJ cell and device provides new breakthrough simultaneously.Because the kind and thickness of inserting metal level have a great impact diffusion and interface interaction, in the present invention, different metal and the impact of different-thickness on magnetospheric perpendicular magnetic anisotropy (PMA) of our research are also different.Wherein, the PMA inserting the CoFeB film of 1nmAg and 1nm Ta is greatly improved compared to the magnetosphere of same thickness individual layer.We are by magnetron sputtering, magnetic hysteresis loop, and the test of atomic force microscope and VASP theory calculate etc. have studied the metal level of insertion variety classes and different-thickness to the impact of the perpendicular magnetic anisotropy of magnetosphere film.
Below by the elaboration of specific embodiment, to further illustrate substantive distinguishing features of the present invention and significant progress, but the present invention is absolutely not only confined to embodiment.
Magnetosphere in following specific embodiment, all for the soft ferromagnetic layer CoFeB film in mtj structure, introduces the film layer structure of the CoFeB film of the metal intercalation containing variety classes and thickness, preparation method, magnetic property and technique effect thereof.The magnetosphere interface perpendicular magnetic anisotropic intensifying method related in the present invention is also applicable to other magnetic layer material in mtj structure, is not limited in CoFeB thin-film material.
Specifically, the film layer structure of the magnetic tunnel-junction of improvement preparation and preparation method as follows:
Membrane structure is MgO sub/FM (1.2nm)/M (t nm)/FM (1.2nm)/Ta (5nm), wherein FM is magnetosphere, M is different metal (Ta, Ag etc.), and t is the thickness of metal level, t=0.5nm ~ 2nm.
Prepare the method for magnetic tunnel junction cell, be specially:
(1) reference layer of improvement preparation on MgO substrate, concrete grammar is the CoFeB film first being sputtered 1.2nm with CoFeB target by magnetron sputtering under the small-power of 20W, required metal targets (Ag or Ta etc.) is used to prepare the metal intercalation that thickness is t again, and then sputter the CoFeB film of 1.2nm, result in formation of the magnetic layer-structure of the improvement inserting the very thin metal intercalation of one deck in CoFeB magnetosphere;
(2) on the reference layer prepared, prepared the barrier layer of the MgO of 1nm by magnetron sputtering by MgO target;
(3) free layer of improvement preparation on the barrier layer prepared, method is consistent with the reference layer in step one;
(4) last in order to protect prepared magnetic tunnel-junction not oxidized, we have added the Ta protective layer of one deck 5nm at top layer.
Further, the film sample of all Slag coating is all for substrate preparation with monocrystalline MgO (001); The Ar air pressure preparing environment of film sample is 0.5Pa; The sputtering power of the sputtering power of the sputtering power of CoFeB to be the sputtering power of 20W, Ta be 40W, Ti to be the sputtering power of 60W, Al be 20W, Ag is 20W.
Embodiment one:
The present embodiment by prepare Single Magnetic layer CoFeB film and insert different-thickness metal layer A g CoFeB film and test its magnetic property, obtain inserting Ag layer and Ag layer thickness to the impact of its perpendicular magnetic anisotropy.
The preparation method of the magnetosphere thin-film material described in the present embodiment can adopt chemical vapour deposition (CVD) (CVD), as liquid deposition, electrolytic deposition and metal-organic chemical vapor deposition equipment etc.; Physical vapour deposition (PVD) (PVD), as hydatogenesis, laser molecular beam epitaxy (laser molecular beam epitaxy, LMBE), pulsed laser deposition (pulsed laser deposition, PLD) and magnetron sputtering (magnetronsputtering) etc.Their general character is that target is deposited on substrate with the form of atom or ion, and difference is mainly that the entrained energy of atom or ion is different.The film utilizing sputtering method to deposit evenly, fine and close, application target is wide, fast growth, can carry out reactive sputtering and the various alloy film of prepared composition, once can also use multiple target rifle, be convenient to the multilayer film that prepared composition is different, therefore widely used by laboratory and industrial quarters.What the present invention selected is magnetron sputtering method.
Embodiment selects magnetically controlled sputter method to prepare magnetosphere film herein.First CoFeB (the wherein atomic ratio Co:Fe:B=40:40:20) target that diameter is 100mm, thickness is 2.5mm is prepared, the purity of target is 99.99% (atomic percent) and required metal targets, and the purity of metal targets is 99.95% (atomic percent).Then use the method for magnetron sputtering, during sputtering, pass into the Ar gas that purity is 99.999%.
The method inserting the magnetosphere CoFeB film of metal layer A g described in preparation, is specially:
(1) on MgO substrate, under the small-power of 20W, first sputtered the CoFeB film of 1.2nm by magnetron sputtering with CoFeB target, the metal intercalation that thickness is t is prepared again by required Ag metal targets, and then sputter the CoFeB film of 1.2nm, result in formation of the magnetic layer-structure of the improvement inserting the very thin metal intercalation of one deck in CoFeB magnetosphere;
(2) in order to prevent the film of preparation oxidized, the Ta cover layer that one deck 5nm is thick has been sputtered at film top.
Concrete technological parameter is as follows:
CoFeB target adopts direct current power power supply, and power is 20W; Sputtering pressure is 0.5Pa; Target-substrate distance is 120mm, and before each sputtering, pre-sputtering 1h is to ensure that target material surface impurity is removed clean.
Ag target adopts direct current power power supply, and power is 10 ~ 20W; Sputtering pressure is 0.5Pa; Target-substrate distance is 120mm, and before each sputtering, pre-sputtering 1h is to ensure that target material surface impurity is removed clean.
Ta target adopts direct current power power supply, and power is 40W; Sputtering pressure is 0.5Pa; Target-substrate distance is 120mm, and before each sputtering, pre-sputtering 1h is to ensure that target material surface impurity is removed clean.
Magnetic layer material described in the present embodiment as shown in Figure 3, its membrane structure is MgO sub/CoFeB (1.2nm)/Ag (t nm)/CoFeB (1.2nm)/Ta (5nm), meanwhile, CoFeB (2.4nm) film of individual layer is also produced out with for referencial use.
Fig. 4 does not insert the reference CoFeB film of metal level through 400 DEG C, the X-ray diffractogram after 1h annealing in process.From XRD collection of illustrative plates, at 400 DEG C, having there is the peak of CoFe (110) in the CoFeB film prepared by us, describes 400 DEG C after 1h annealing in process, the annealing conditions of 1h can make CoFeB film crystallization, and presents the texture of CoFe (110).
Fig. 5 is the magnetic hysteresis loop in the horizontal direction of the CoFeB film of individual layer and vertical direction.Can find out that the vertical direction of CoFeB film (comprising 1.2nm and 2.4nm) not inserting any metal level is no more than 2 with the ratio of the coercive force of horizontal direction from the result of chart.
Fig. 6 is the magnetic hysteresis loop in the horizontal direction of the CoFeB film inserting 1nm and 0.5nm Ag and vertical direction.And table 1 is the film of individual layer CoFeB (1.2nm) and (2.4nm) and inserts the vertical direction of CoFeB film of different metal levels and the coercitive value of horizontal direction and their ratio.When the vertical direction of film and the ratio of the coercive force of horizontal direction are larger, show the vertical orientated better of film.Thus, as can be seen from the data of Fig. 6 associative list 1, insert the vertical direction of the film of 0.5nm metal A g and be less than 2 with the ratio of the coercive force of horizontal direction, reason is that the metal level inserted is too thin so that do not form good interface with CoFeB layer, interface interaction is not formed, and causes perpendicular magnetic anisotropy to be significantly improved.Illustrate whether the improvement of CoFeB layer perpendicular magnetic anisotropy follows the thickness of inserted metal to have very large relation thus.And the ratio of the vertical direction of CoFeB film and the coercive force of horizontal direction that insert 1nm Ag is 4.32, considerably beyond the ratio of the coercive force of the vertical direction of individual layer CoFeB film and horizontal direction.Illustrate thus and insert the perpendicular magnetic anisotropy that 1nm Ag can significantly improve CoFeB film in CoFeB film.Reason is the diffusion of Ag and defines the interface of metal/CoFeB with CoFeB layer, improves the perpendicular magnetic anisotropy of CoFeB.
Table 1
In order to further confirmatory experiment result, use VASP first-principles calculations and compare individual layer CoFeB (2.4nm) film and insert 0.5nm Ag and 1nm Ag film unit cross-sectional area on magnetic anisotropy can (MAE).Result of calculation is as shown in table 2.When the value of the MAE calculated be on the occasion of time, illustrate that film has perpendicular magnetic anisotropy, and MAE is larger, then the perpendicular magnetic anisotropy of film is larger.When the value of MAE is negative value, then illustrate that film has the anisotropy in face.The result that we calculate as shown in Figure 7.It is maximum that result shows the MAE inserted on the unit cross-sectional area of the film of 1nm Ag, and the MAE inserted on the unit cross-sectional area of the film of 0.5nm Ag is minimum, equally also show in CoFeB film, insert the perpendicular magnetic anisotropy that 1nm Ag can improve CoFeB film, match with experimental result.
Table 2
Simultaneously, we also compares the MAE of the CoFeB layer of the Ag metal level inserting 2nm, as can be seen from Table 2, the MAE inserting the unit are of the CoFeB of the Ag of 2nm thickness is less than the value of individual layer CoFeB, illustrate that the thickness of 2nm is for too thick Ag metal level thus, be unfavorable for the perpendicular magnetic anisotropy improving CoFeB.
The present embodiment illustrates that the Ag metal level inserting 1nm can well improve the magnetospheric perpendicular magnetic anisotropy of CoFeB.
Embodiment two:
The present embodiment is by preparing the CoFeB film of the metal level Ta of Single Magnetic layer CoFeB film and insertion different-thickness and testing its perpendicular magnetic anisotropy of its Performance comparision.
The method inserting the magnetosphere CoFeB film of metal level Ta described in preparation, is specially:
(1) on MgO substrate, under the small-power of 20W, first sputtered the CoFeB film of 1.2nm by magnetron sputtering with CoFeB target, the metal intercalation that thickness is t is prepared again by required Ta metal targets, and then sputter the CoFeB film of 1.2nm, result in formation of the magnetic layer-structure of the improvement inserting the very thin metal intercalation of one deck in CoFeB magnetosphere;
(2) in order to prevent the film of preparation oxidized, the Ta cover layer that one deck 5nm is thick has been sputtered at film top.
Concrete technological parameter is as follows:
CoFeB target adopts direct current power power supply, and power is 20W; Sputtering pressure is 0.5Pa; Target-substrate distance is 120mm, and before each sputtering, pre-sputtering 1h is to ensure that target material surface impurity is removed clean.
Ta target adopts direct current power power supply, and power is 40W; Sputtering pressure is 0.5Pa; Target-substrate distance is 120mm, and before each sputtering, pre-sputtering 1h is to ensure that target material surface impurity is removed clean.
Magnetic layer material described in the present embodiment, its membrane structure is MgO sub/CoFeB (1.2nm)/Ta (t nm)/CoFeB (1.2nm)/Ta (5nm), and wherein t is 0.5nm and 1nm.
Fig. 8 is the magnetic hysteresis loop in the horizontal direction of the CoFeB film inserting 1nm and 0.5nm Ta and vertical direction.The data of associative list 1 can be found out, the ratio of the vertical direction of film and the coercive force of horizontal direction that insert 0.5nm metal Ta is also greater than the value of individual layer CoFeB (1.2nm).And the ratio of the vertical direction of CoFeB film and the coercive force of horizontal direction that insert 1nm Ta is 2.38, have also exceeded the ratio of the vertical direction of individual layer CoFeB film and the coercive force of horizontal direction.Illustrate thus and insert the perpendicular magnetic anisotropy that 1nm Ta also can improve CoFeB film in CoFeB film.Reason may be the diffusion of Ta and define the interface of metal/CoFeB with CoFeB layer, improves the perpendicular magnetic anisotropy of CoFeB.
Same inserted in CoFeB film by first-principles calculations the metal level Ta of 0.5nm, 1nm and 2nm MAE, result of calculation is as shown in table 3.Obviously can find out that the MAE of the CoFeB film of the metal Ta layer inserting different-thickness is higher than the MAE of individual layer CoFeB from table, illustrate that the Ta layer in insertion 0.5nm ~ 2nm thickness range can improve the magnetic anisotropy of CoFeB layer thus.
Table 3
The present embodiment illustrates that the Ta metal level inserted in 0.5nm ~ 2nm thickness range can well improve the magnetospheric perpendicular magnetic anisotropy of CoFeB.By the present embodiment with insert the test result of Ag metal level in embodiment one at CoFeB film compared with, although insert the perpendicular magnetic anisotropy that certain thickness Ta layer and Ag layer can both improve CoFeB film, the perpendicular magnetic anisotropy inserting the CoFeB film of 1nm Ag metal level is obviously large than the perpendicular magnetic anisotropy of the CoFeB film inserting Ta layer.This may be because the mismatch ratio (1%) of the lattice constant of Ag and CoFeB is less than the mismatch ratio (4%) of the lattice constant of Ta and CoFeB.
Embodiment three:
The present embodiment by first-principles calculations Single Magnetic layer CoFeB film and insert different-thickness metal level Ti CoFeB film anisotropy energy and compare their size.
Result of calculation is as shown in table 4.Obviously can find out that from table the MAE of the MAE of the CoFeB film of the metal Ti layer inserting 0.5nm and individual layer CoFeB film is lower slightly, and the MAE inserting the CoFeB film of the metal Ti layer of 1nm will be greater than the CoFeB film of individual layer greatly, it is almost the relation of 2 times.And when the thickness of metal level Ti is increased to 2nm time, the value of MAE becomes suddenly negative value, means that the magnetosphere of the metal Ti inserting 2nm loses perpendicular magnetic anisotropy.
The magnetic anisotropy that can improve CoFeB layer at the Ti layer inserting 1nm is described thus.
Table 4
Embodiment four:
The present embodiment by first-principles calculations Single Magnetic layer CoFeB film and insert different-thickness metal layer A l CoFeB film anisotropy energy and compare their size.
Result of calculation is as shown in table 5.Obviously can find out that the MAE of the CoFeB film of the metal Al layer inserting 0.5nm and 1nm is higher than the MAE of individual layer CoFeB from table, illustrate that the Al layer in insertion 0.5nm ~ 1nm thickness range can improve the magnetic anisotropy of CoFeB layer thus.And magnetospheric perpendicular magnetic anisotropy can be reduced on the contrary when Al metal level too thick (reaching 2nm) time.
Table 5
The particular types that inserts provided by the invention is compared with single layer magnetic film with the magnetic thin film of the metal level of thickness, inserts the perpendicular magnetic anisotropy that thin metal layer effectively can improve magnetic thin film, is conducive to preparing high density, the magnetic tunnel junction cell of low-power consumption and device.The present invention inserts thin metal layer to improve its perpendicular magnetic anisotropic in magnetosphere, and this thin metal layer material is not limited in Ag, Ta, Ti and Al of mentioning in embodiment, can also be other nonmagnetic material such as Cu, Au.The thickness range of this metal level is 0.5nm ~ 2nm.
Those skilled in the art will readily understand; the foregoing is only preferred embodiment of the present invention; not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. a magnetic tunnel junction cell, comprises substrate, is attached to the reference layer on described substrate, the free layer being attached to the barrier layer on described reference layer and being attached on described barrier layer; It is characterized in that, described reference layer is identical with the structure of described free layer, includes the first magnetosphere, metal level and the second magnetosphere; Strengthen the interface perpendicular magnetic anisotropy in the first magnetosphere and the second magnetosphere by described metal level, improve the perpendicular magnetic anisotropic of magnetic tunnel junction cell.
2. magnetic tunnel junction cell as claimed in claim 1, it is characterized in that, described first magnetospheric thickness is equal with described second magnetospheric thickness, and the thickness of described metal level is 0.5nm ~ 2nm.
3. magnetic tunnel junction cell as claimed in claim 1, it is characterized in that, the material of described metal level is nonmagnetic material.
4. magnetic tunnel junction cell as claimed in claim 3, it is characterized in that, the material of described metal level is Ag, Ta, Ti, Al, Cu or Au.
5. magnetic tunnel junction cell as claimed in claim 4, it is characterized in that, the material of described metal level is Ag, and thickness is 1nm.
6. magnetic tunnel junction cell as claimed in claim 1, it is characterized in that, described magnetic tunnel junction cell also comprises the protective layer be attached on described free layer.
7. magnetic tunnel junction cell as claimed in claim 6, it is characterized in that, the material of described protective layer is Ta.
8. a preparation method for magnetic tunnel junction cell, is characterized in that, comprises the steps:
(1) on substrate, prepare the first magnetosphere by the method for magnetron sputtering, described first magnetosphere prepares metal level, and prepare the second magnetosphere on described metal level;
(2) on described second magnetosphere, barrier layer is prepared by the method for magnetron sputtering;
(3) on described barrier layer, free layer is prepared; The second magnetosphere that described free layer comprises the first magnetosphere, is attached to the metal level on described first magnetosphere and is attached on described metal level;
(4) on described free layer, prepare protective layer, thus obtain magnetic tunnel junction cell;
Wherein, described first magnetospheric thickness is equal with described second magnetospheric thickness, and the thickness of described metal level is 0.5nm ~ 2nm.
9. preparation method as claimed in claim 8, it is characterized in that, the material of described metal level is Ag, Ta, Ti, Al, Cu or Au.
10. preparation method as claimed in claim 8, it is characterized in that, the material of described metal level is Ag, and thickness is 1nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510359389.3A CN104993046A (en) | 2015-06-25 | 2015-06-25 | MTJ unit and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510359389.3A CN104993046A (en) | 2015-06-25 | 2015-06-25 | MTJ unit and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104993046A true CN104993046A (en) | 2015-10-21 |
Family
ID=54304829
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510359389.3A Pending CN104993046A (en) | 2015-06-25 | 2015-06-25 | MTJ unit and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104993046A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106611813A (en) * | 2015-10-23 | 2017-05-03 | 爱思开海力士有限公司 | Electronic device and method for fabricating the same |
| WO2022021169A1 (en) * | 2020-07-30 | 2022-02-03 | 华为技术有限公司 | Magnetic tunnel junction and storage unit |
| CN115020099A (en) * | 2022-05-26 | 2022-09-06 | 中国科学院金属研究所 | Method for enhancing vertical magnetic anisotropy of NdFeB-based permanent magnet thick film |
| CN115595541A (en) * | 2021-06-28 | 2023-01-13 | 北京超弦存储器研究院（Cn） | Preparation method of tunneling magneto-resistance and magnetic random access memory based on principle of adjusting RA value by sputtering power |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102024903A (en) * | 2009-09-11 | 2011-04-20 | 三星电子株式会社 | Magnetic memory device |
| CN103503067A (en) * | 2011-04-25 | 2014-01-08 | 国际商业机器公司 | Magnetic stacks with perpendicular magnetic anisotropy for spin momentum transfer magnetoresistive random access memory |
| CN103531708A (en) * | 2012-07-06 | 2014-01-22 | 国际商业机器公司 | Domain wall motion in perpendicularly magnetized wires having artificial antiferromagnetically coupled multilayers with engineered interfaces |
| CN103907156A (en) * | 2011-09-22 | 2014-07-02 | 高通股份有限公司 | Thermally tolerant perpendicular magnetic anisotropy coupled elements for spin-transfer torque switching device |
| CN104051610A (en) * | 2013-03-15 | 2014-09-17 | 三星电子株式会社 | Magnetic junctions having insertion layers and magnetic memories using the magnetic junctions |
-
2015
- 2015-06-25 CN CN201510359389.3A patent/CN104993046A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102024903A (en) * | 2009-09-11 | 2011-04-20 | 三星电子株式会社 | Magnetic memory device |
| CN103503067A (en) * | 2011-04-25 | 2014-01-08 | 国际商业机器公司 | Magnetic stacks with perpendicular magnetic anisotropy for spin momentum transfer magnetoresistive random access memory |
| CN103907156A (en) * | 2011-09-22 | 2014-07-02 | 高通股份有限公司 | Thermally tolerant perpendicular magnetic anisotropy coupled elements for spin-transfer torque switching device |
| CN103531708A (en) * | 2012-07-06 | 2014-01-22 | 国际商业机器公司 | Domain wall motion in perpendicularly magnetized wires having artificial antiferromagnetically coupled multilayers with engineered interfaces |
| CN104051610A (en) * | 2013-03-15 | 2014-09-17 | 三星电子株式会社 | Magnetic junctions having insertion layers and magnetic memories using the magnetic junctions |
Non-Patent Citations (2)
| Title |
|---|
| S.IKEDA ET AL.: "A perpendicular-anisotropy CoFeB-MgO magnetic tunnel junction", 《NATURE MATERIALS》 * |
| TING HUANG ET AL.: "Effect of Ultrathin Inserted Ag Layer on Perpendicular Magnetic Anisotropy of CoFeB Thin Film", 《IEEE TRANSACTIONS ON MAGNETIC》 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106611813A (en) * | 2015-10-23 | 2017-05-03 | 爱思开海力士有限公司 | Electronic device and method for fabricating the same |
| US10516099B2 (en) | 2015-10-23 | 2019-12-24 | SK Hynix Inc. | Electronic device and method for fabricating the same |
| CN106611813B (en) * | 2015-10-23 | 2020-04-14 | 爱思开海力士有限公司 | Electronic device and method of manufacturing the same |
| WO2022021169A1 (en) * | 2020-07-30 | 2022-02-03 | 华为技术有限公司 | Magnetic tunnel junction and storage unit |
| CN115595541A (en) * | 2021-06-28 | 2023-01-13 | 北京超弦存储器研究院（Cn） | Preparation method of tunneling magneto-resistance and magnetic random access memory based on principle of adjusting RA value by sputtering power |
| CN115020099A (en) * | 2022-05-26 | 2022-09-06 | 中国科学院金属研究所 | Method for enhancing vertical magnetic anisotropy of NdFeB-based permanent magnet thick film |
| CN115020099B (en) * | 2022-05-26 | 2023-11-03 | 中国科学院金属研究所 | Method for enhancing vertical magnetic anisotropy of NdFeB-based permanent magnet thick film |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11930717B2 (en) | Minimal thickness synthetic antiferromagnetic (SAF) structure with perpendicular magnetic anisotropy for STT-MRAM | |
| Nistor et al. | Pt/Co/oxide and oxide/Co/Pt electrodes for perpendicular magnetic tunnel junctions | |
| EP2839501B1 (en) | Free layer with high thermal stability for magnetic device applications by insertion of a boron dusting layer | |
| Ding et al. | Tunable perpendicular magnetic anisotropy in GdFeCo amorphous films | |
| KR101287370B1 (en) | Copt multilyers having an inverted structure and method for preparing the same | |
| CN110350082A (en) | The method of magnetic device and offer magnetic device including Thomas Hessler compound | |
| US10858730B2 (en) | Multilayer thin films exhibiting perpendicular magnetic anisotropy | |
| CN101276879B (en) | Double freedom layer vertical ferromagnetism tunnel junction structure | |
| CN104993046A (en) | MTJ unit and manufacturing method thereof | |
| US10903416B2 (en) | Alloy thin films exhibiting perpendicular magnetic anisotropy | |
| JP2008135676A (en) | Cobalt-iron-silicon-boron/platinum multilayer thin film exhibiting perpendicular magnetic anisotropy | |
| CN109564968A (en) | With the magnetospheric magnetic tunnel junction device for being in simple conic state | |
| Jung et al. | Perpendicular magnetic anisotropy properties of CoFeB/Pd multilayers | |
| CN108695431A (en) | A kind of flattening method of magnetic tunnel junction | |
| Sellmyer et al. | Magnetism of nanophase composite films | |
| KR101519767B1 (en) | Multilayers with perpendicular magnetic anisotropy | |
| US20070215955A1 (en) | Magnetic tunneling junction structure for magnetic random access memory | |
| Kaiser et al. | High negative tunneling magnetoresistance in magnetic tunnel junctions with a ferrimagnetic CoFe–Gd electrode and a CoFe interface layer | |
| Poon et al. | Amorphous ferrimagnets: an ideal host for ultra-small skyrmions | |
| Mo et al. | Magnetic properties of perpendicularly orientated L1 0 FePt nanoparticles | |
| Poon et al. | Amorphous Ferrimagnets: an Ideal Host for Ultra-Small Skyrmions at Room Temperature | |
| CN107587109B (en) | Composite multi-layer membrane structure with high vertical off setting field and big overturning field platform | |
| CN107958950A (en) | Production method, MTJ device and the STT-MRAM of MTJ device | |
| You et al. | Exchange coupling and magnetic properties of Sm–Co/Fe65Co35 multi-layered films | |
| CN116056549A (en) | Magnetic memory cell, preparation method thereof, magnetic memory array and memory |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20151021 |
|
| RJ01 | Rejection of invention patent application after publication |